Baffle for a sound producing device

ABSTRACT

A baffle which is used in a sound producing device and which includes overlying first and second disks having coincident axes. The first disk is rotative about its axis relative to the second disk and has a plurality of equi-angularly spaced and equiradially disposed slotted openings formed therein. The second disk also has a plurality of equi-angularly spaced, equi-radially disposed slotted openings formed therein. Each slotted opening in the first disk is disposed at an angle to a radial line passing through the opening. Each slotted opening in the second disk is disposed at an angle to a radial line extending through such opening with the angle of the second disk opening differing from the angle of the first disk openings so that upon rotation of the first disk relative to the second disk selected portions of the slotted openings in the second disk will be covered by the first disk openings to produce circumferentially spaced openings through the baffle located a selected radial distance from the axes of the disks.

United States Patent [191 Buckwalter [111 3,826,333 [451 July 30, 1974 DEVICE [76] Inventor: James K. Buckwalter, 65 Robert E.

Lee Dr., Wilmington, NC. 28401 [22] Filed: Mar. 21, 1973 [21] Appl. No.: 343,251

'52 Us. 01...... 181/31 B, 13 1 31 A 51 Int. c|...... GlOk 13/00, H04; 1/28 581 Field ofSedrch 181/31 8,31 A,31 R; v 340/405 [56] References Cited UNITED sTATEs PATENTS 1,953,523 4/1934 Wolff 181/31 B 2,193,399 3/1940 Fisher 181/31 B 2.196.342v 4/1940 Ruttenbcrg 181/31 B 2,515,031 7/1950 Black, Jr. 181/31 B 2,580,916 1/1952 Hodge 181/31 B 3,121,220 2/1964 Buckwalter 340/405 FOREIGN PATENTS OR APPLICATIONS 102,888 12/1937 Australia 181/31 B 8/1950 Great Britain 181/31 B Primary ExaminerStephen J. Tomsky Attorney, Agent, or Firm-Oltsch & Knoblock [57] ABSTRACT A baffle which is used in a sound producing device and which includes overlying first and second disks having coincident axes. The first disk is rotativeabout its axis relative to the second disk and has a plurality of equi-angularly spaced and equi-radially disposed slotted openings formed'thereinvThe second disk also has a plurality of-equi-angularly spaced, equi-radially disposed slotted openings formed therein. Each slotted opening in the first disk is disposed at an angle to a radial line passing through the opening. Each slotted opening in-thesecond disk is disposed at an angle to a radial line extending through such opening with the angle of the second disk opening differing from the angle of the first disk openings so that upon rotation of the first disk relative to the second disk selected portions of the slotted openings in the second disk will be covered by the first disk openings to produce circumferentially spaced openings through the baffle located a selected radial distance from the axes of the disks.

4 Claims, 5 Drawing Figures 1 BAFFLE FOR A SOUND PRODUCING DEVICE BACKGROUND OF THE INVENTION I speakers. Such speakers are generally inexpensive and tend to be high-pitched and of unfavorable tone quality. To improve the quality of such small speakers, various baffling devices have been placed in front of the speakers to dampenspeaker vibrations. Additionally, the mountings for such speakers have been constructed so as to place still or standing air columns to the front and to the rear of the speakers. In this invention, the baffle is designed to enhance the tone quality of a speaker by taking advantage of the known fact that the greatest bass response of a speaker is generated at the outer edge of the speaker cone, while the treble response is generated. mostly from the center of the cone.

I SUMMARY OF-TI-IE INVENTION This invention relates to a baffle which is for use in a sound producing device and which includes first and second overlying disks having coincident axes. The first disk is rotative relative to the second disk about said axes and has a'plurality of equi-angularly spaced and equi-r'adially disposed slotted openings therein. The

second disk also has a plurality of equi-angularly spaced, equi-radially disposed slotted openings therein. The slotted openings in each disk'are angled in their longitudinal dimension relative to a radial line which extends outwardly from the axes of the disks. All slotted openings in the first disk are similarly angled butat a different angle from the angle of the openings in the first disk,so that upon rotation of the first disk relative to the second disk, portions of the first disk openings will overlie portions of the openings in the second disk to produce circumferentially spaced openings through the baffle of a selected radial distance from the axesof the disks. In this manner, openings of variable size can be formed in the baffle at selected radial distances-from the axial center of the speaker cone so. as to accentuate the-tone response at the open portion of the baffle while muting the tone response at the unopened or closed portion of the baffle. I

Accordingly, it is an objectof this invention to provide a unique baffle which can be used in a sound producing device to accentuate certain tones thereof.

Another object of this invention is to provide a baffle of economical construction for use in a sound produc* ing device to produce s'elected'accentuated tones. Other objects of this invention will become apparent upon a reading ,of the inventions description.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 3 is an end view of the sound producing device 'showingthe baffle in one operative open position as seen from line 3-3 of FIG. 2.

FIG. 4 is an end view of the baffle device shown in FIG. 3 with the baffle being positioned in a second operative open position.

' FIG. 5 is an end view of the baffle of FIG. 3 showing the baffle in a closed position.

DESCRIPTION OF THE PREFERRED EMBODIMENT The preferred embodiment illustrated is not intended I to be exhaustive or to limit the inventionto the precise form disclosed. Itv is chosen and described in-order to vbest explain the principles of the invention and its application and practical use to thereby enable others skilled in the art to best utilize the invention.

The sound device shown in FIG. 1 and designated by the reference numeral 10 includes a casing 12 which houses suitable electronic components (not shown) which are controlled by dials 14 and which serve to produce and amplify sound generating waves. The type of sound, whether it be musical,. speaking, or background such as that of breaking waves or rain, and the specific type ofelectronic apparatus to produce this sound, as controlled by dials 14, are not of direct patentable significance. Casing 12 includes a semi-circular 7 18 of casing 12. The inner surface of tubular member 22 is-preferably lined with sound absorbing material 28 which extends between cone 26 of the speaker and casing opening 18 at the forward side of the speaker. Cone 26 is located coaxially with openings 18. Sound absorbing material 28 can be formed of any number of materials, such as urethane foam. If desired, a sound muffling disk 30 can be positioned across the inside of tubular member 22 between'speaker 24 and casing opening 18 at the back side of the speaker. Disk 30 maybe of a cotton composition.

Mounted within each opening 18 in casing 12 is the baffle 32 of this invention. Each baffle 32 is of a similar construction and includes an inner disk 34 and an outer disk 36. Disk 34 of each baffle 32 is fixedly attachedto casing 12 and located at the inner edge of a casing flange 20 in coaxial alignment with the opening 18 formed by the flange. Disks 34 and 36 are coaxial with each disk 36 overlying a disk 34 and being joined thereto-for pivotal movement relative to the disk 34' about their axes by a rivet 38 or similar pivot member. The outer diameters of disks 36 are slightly less than the inner diameters of openings 18 in casing 12 so that the disks may rotate within the openings without contacting flanges 20 of the casing. Each disk 34 includes a plurality of equi-angularly spaced and equi-radially disposed slotted openings 40 formed therein. Each opening 40 preferably tapers in a directiontoward the axis 39 of disk 34 and includes a large outer arcuate end portion 42 and a smaller inner arcuate end portion 7 44. Each opening .40 is similarly angled along its longi- Each disk 36 also has a plurality of slotted openings 40' formed therein. Openings 40' in each disk are equal in number. to openings 40 ineach disk 34 and are equiangularly spaced and equi-radially disposed. Each opening 40' in disks 36 is preferably tapered toward the axis 39' of the disk and includes a large outer arcuate end portion 42 and a smaller inner arcuate end portion 44. Openings 40 and openings 40 are preferably spacedthe same radial distance from the axes of disks 34 and 36 and are preferably of like size. Each opening 40' in disks 36 is angled along its longitudinal dimension as measured between end portions 42' and 44' relative to a radial line 41' extending through the axis 39 of the disk and the center of end portion 42 of the opening; Slotted openings 40 are preferably angled oppositely to slotted openings 40 so that rotation of each disk 34'causes openings 40 and 40 of each baffle 32 to cross and cooperate to define a plurality of equiangularly spaced, equi-radial openings 46 through the baffle which vary in size and radial location depending upon the angular position of disk 36 relative to underlying disk 34 of the baffle. The angular relationship of openings 40 and 40' in disks 34 and 36 of each baffle 32 and'the location of openings 46 in the baffle are best illustrated in FIGS. 35.

In FIG. 3 it'will be observed that disk 36 has been rotated so that each opening 46 is of a maximum size located at amaximum radial distance from the axis of the disk and baffle. In FIG. 4 disk 36 has been rotated as indicated by arrows 48 so that each opening 46 therein is of a minimum size located a minimum radial distance 1. In a sound producing device having speaker means for emitting sound waves in a generally circular pattern along an axis, a baffle comprising first and second disks, said disks having coincident axes, said first disk overlying said second disk and being rotative relative to said second disk about said disk axes, said disk axes coinciding'with said axis along which said sound waves are emitted, said first disk having a plurality of equivangularly spaced and equi-radially disposed slotted from the axis of the disk and baffle. In FIG. 5, it can be I seen that continued rotation of outer baffle disk 36 causes the openings 40 and 40' therein to be offset openings formed therein, each first disk opening having an outer end portion and an inner end portion and extending at a similar angle in its longitudinal dimension as measured between said end portions to a radial line extending from said disk axes and through the opening outer end portion, said second disk having aplurality of equi-angularly spaced and equi-radially disposed slotted openings formed therein, said second diskopenings being equal in number to said first disk openings, each second disk opening having an outer end portion and an inner end portion and extending at a similar angle in its longitudinal dimension as measured 'between its said end portions to a radial line extending from said disk axes through its outer end portion, said first and second disk openings overlapping upon rotation of said first disk relative to said second disk, said angle of said first disk openings differing from the angle of said second disk openings whereby selected portions of said first disk openings upon rotation of said first disk'relative to said second disk will overlie portions of said second disk openings to produce circumferentially ing at the center of the speaker cone to pass through openings 46 in the baffle and thus be accentuated. It has been found that by tapering slotted openings 40 and 40', each opening 46 is of a larger area when located at the outer margin of the baffle than when located near the center of the baffle to better accommodate bass accentuation. Obviously, outer disk 36 of each baffle can be'located between the two extreme open positions illustrated in FIGS. 3 and 4 to provide a selected combination of bass and treble accentuation. To facilitate rotative movement of disk 36 relative to disk 34 of each baffle 32, diametrically spaced tabs 50, are formed on the outer surface, of each disk 36.

axes.

, 4. The baffle of claim 4 wherein the inner and outer end portions of said first and second disk openings are arcuate with all of said outer end portions of said first and second disk openings being of the same size and Y with all said inner end portions of said first and second the same size.

disk openings .being of. 

1. In a sound producing device having speaker means for emitting sound waves in a generally circular pattern along an axis, a baffle comprising first and second disks, said disks having coincident axes, said first disk overlying said second disk and being rotative relative to said second disk about said disk aXes, said disk axes coinciding with said axis along which said sound waves are emitted, said first disk having a plurality of equiangularly spaced and equi-radially disposed slotted openings formed therein, each first disk opening having an outer end portion and an inner end portion and extending at a similar angle in its longitudinal dimension as measured between said end portions to a radial line extending from said disk axes and through the opening outer end portion, said second disk having a plurality of equi-angularly spaced and equi-radially disposed slotted openings formed therein, said second disk openings being equal in number to said first disk openings, each second disk opening having an outer end portion and an inner end portion and extending at a similar angle in its longitudinal dimension as measured between its said end portions to a radial line extending from said disk axes through its outer end portion, said first and second disk openings overlapping upon rotation of said first disk relative to said second disk, said angle of said first disk openings differing from the angle of said second disk openings whereby selected portions of said first disk openings upon rotation of said first disk relative to said second disk will overlie portions of said second disk openings to produce circumferentially spaced openings in said baffle at a selected radial distance from said disk axes.
 2. The baffle of claim 1 wherein said disk first and second disk openings are tapered toward said axes with each opening including a large outer end portion and a smaller inner end portion.
 3. The baffle of claim 2 wherein said disk first and second disk openings are equally spaced from said axes.
 4. The baffle of claim 4 wherein the inner and outer end portions of said first and second disk openings are arcuate with all of said outer end portions of said first and second disk openings being of the same size and with all said inner end portions of said first and second disk openings being of the same size. 